Fluoride concentration of bottled waters and beverages in Hong Kong

Abstract

Objective: To report on the concentration of fluoride ions in the popular industrialized bottled waters and beverages in Hong Kong. Method: The most popular brands of bottled waters and beverages, i.e. the largest sales by volume, as reported by marketing researches conducted in Hong Kong were selected for investigation in this study. Two samples with different batch number of each selected drink were purchased from retail outlets. The concentration of fluoride ions in each sample drink was determined by using a fluoride ion selective following a standard protocol. The measurement was performed in a research laboratory of the University of Hong Kong by a trained investigator. Tap water (0.5 ppm) and deionized water were used as the positive and the negative controls for the measurements.

Results: Fluoride concentration of 13 brands of bottled waters and 11 brands of beverages were determined. All 5 distilled water and 3 mineralized water were found to have fluoride concentrations <0.1 ppm. A large variation was seen in natural mineral/spring water, ranging from <0.1 to 1.31 ppm. Approximately 70% of the selected bottled waters had a fluoride concentration <0.1ppm. Tea beverages were found to have a relatively high fluoride concentration, ranging from 0.69 to 2.76 ppm. The highest one was lemon tea while the lowest one is green tea with honey. The fluoride concentration in the other studied non-tea beverages ranged from <0.1 to 0.5ppm, and most of them (75%) contained <0.1 ppm fluoride. The differences in the measured fluoride concentration between the two samples of the same brand of drink was small, nearly all were <0.1 ppm.

Conclusion: Concentration of fluoride in the popular bottled drinks in Hong Kong, except tea products, is generally low and variation between different batches is small.